Tutorial Lab 4

Question 1

Name and describe the two parts of the vertebrate skeleton

Answer 1

Axial skeleton - consist of skull, vertebrae and ribs

Appendicular skeleton - Consist of pectoral and pelvic girdles and the bones of the appendages

Question 2

Briefly describe the skull of the perch

Answer 2

• Outer skull is an armour of dermal bone (bone that forms in the dermis of the skin)
• Inner skull composed of endochondral bone
• Inner skull is the cranium (encases the brain)

Question 3

Describe the vertebrae of the perch

Answer 3

Vertebrae are a series of endochondral bones forming the vertebral column. The large central portion of each is the centrum (with a canal for the notochord)

Question 4

The arch of bone surrounding a protecting the spinal cord is called the __________

Answer 4

Neural arch

Question 5

Describe the vertebral column of a perch

Answer 5

Divided into the TRUNK and the TAIL sections. First two trunk vertebrae lack ribs, but the rest have ribs, up until the caudal section. But they do possess a ventral portion that forms a hemal arch, surrounding the blood vessels.

Question 6

Describe the median fins of the perch

Answer 6

These dorsal fins have fin rays for support. The anterior dorsal fin has ossified fin rays for support, while the fin rays of the posterior dorsal fin are not ossified (flexible). Only the first two fin rays of the anal fin are ossified, and the caudal fin is composed of soft, unossified fin rays

Question 7

Describe the pectoral girdle and fins of the perch

Answer 7

The pectoral fins are attached to the bony pectoral girdle. This is fused to the head and the two move in unison. The fins are supported by soft fin rays

Question 8

Describe the pelvic girdle and fins of the perch

Answer 8

The pelvic fins are attached to a pelvic girdle, which is composed of two pelvic plates. The girdle is suspended in muscle. Only the medial fin rays are bony

Question 9

Describe the skin and scales of the perch

Answer 9

The outer epidermis of fish is really thin, and filled with unicellular mucous glands. The inner dermis is composed of fibrous connective tissue and is attached to the muscles by connective tissue. The scale are located within the dermis.

Question 10

Describe the skull of the rat

Answer 10

Maxilla (top of head) and premaxilla (front of head) are the tooth-bearing bones. The mandible is the jaw bone. The occipital is the bone in the back of the head. Within the jaw, there are both incisor and molar teeth

Question 11

In mammals, the mouth has been separated by a shelf of bone and soft tissue called the __________

Answer 11

Palate

Question 12

Describe the vertebral column of the rat

Answer 12

The first cervical vertebra is the atlas, and it causes the up-down motion of the head. The second vertebra us the axis, which causes the left-right motion. Thoracic vertebrae bear ribs while lumbar vertebrae do not. The sacrum is formed by the fusion of 3-5 sacral vertebrae. Caudal vertebrae number vary between species

Question 13

The evolution of what structure is correlated with the differentiation into thoracic and lumbar vertebrae?

Answer 13

Diaphragm, a sheet of muscle which separates the two regions

Question 14

Describe the ribs of the rat

Answer 14

All ribs attach dorsally to the thoracic vertebrae. True ribs (7 pairs) attach directly to the sternum, while false ribs (3 pairs) attach to the rib anterior. Floating ribs (3 pairs) do not have any ventral attachments. The last element of the sternum, the xiphisternum, is attached to a xiphoid process composed of cartilage

Question 15

Describe the scapulae and clavicles of the rat

Answer 15

Scapulae are the large “shoulder” bones, and clavicles are are the smaller accessory bones attached

Question 16

Describe the location of the humerus, radius, ulna, carpals, metacarpals and phalanges

Answer 16

Humerus: large upper-arm bone
Radius: one of the lower arm bones
Ulna: smaller lower arm bone
Carpals: Bottom bones of hand (near the wrist)
Metacarpals: first bone of finger
Phalanges: second bone of finger

Question 17

Describe the skin of mammals (specifically rats?)

Answer 17

The epidermis of mammals is very very thick, with many layers of dead cells for protection. The dermis is composed of dense, fibrous connective tissue and contains blood vessels, nerve fibres, sensory endings, arrector pilli muscles, glands, and hair follicles.
The dermis also contains oil-secreting sebaceous glands and sweat glands

Question 18

Describe the inner mechanisms of the testes of a rat

Answer 18

Seminiferous tubules coil up around the the testis, which mature sperm in the centers of some of these tubules

Question 19

Describe the ovary of the rat

Answer 19

The ovary is filled with sac-like follicles in which ova (eggs) mature. When a follicle is ripe (graafian follicle) and it’s ovum is mature, it bursts, releasing the ovum, which travels down the oviduct, being propelled in the uterus by the movement of cilia.

Question 20

Describe the arteries and veins of the head of the rat

Answer 20

The aorta divides into the innominate artery and the aortic arch. The aortic arch branches into the left common carotid artery and the left subclavian artery, then continues as the dorsal aorta.
The left CCA and left SA move to the submaxillary gland
The innominate artery branches into the right common carotid artery (carries blood to the head), and the right subclavian artery (carries blood to the right front leg).
The venous system (system including the venal cavae) in the head region carried deoxygenated blood to the heart.

Question 21

Describe the visceral arteries of the rat

Answer 21

Intercostal arteries - arise from the dorsal sorts and go to the ribs
Coeliac artery - First large artery branching off the aorta
Splenic artery - Branches off coeliac, supplies blood to spleen and pancreas
Hepatic artery - Branches off of coeliac, supplies blood to liver
Gastric artery - Branches off of coeliac, supplies blood to stomach
Superior Mesenteric Artery - Branches off dorsal aorta
Renal arteries - Branch off dorsal aorta, lead to kidneys

Question 22

Describe the arteries and veins of the head of the rat

Answer 22

The aorta divides into the innominate artery and the aortic arch. The aortic arch branches into the left common carotid artery and the left subclavian artery, then continues as the dorsal aorta.
The left CCA and left SA move to the submaxillary gland
The innominate artery branches into the right common carotid artery (carries blood to the head), and the right subclavian artery (carries blood to the right front leg).
The venous system (system including the venal cavae) in the head region carried deoxygenated blood to the heart.

Question 23

Name and describe the visceral arteries of the rat

Answer 23

Intercostal arteries - arise from the dorsal sorts and go to the ribs
Coeliac artery - First large artery branching off the aorta
Splenic artery - Branches off coeliac, supplies blood to spleen and pancreas
Hepatic artery - Branches off of coeliac, supplies blood to liver
Gastric artery - Branches off of coeliac, supplies blood to stomach
Superior Mesenteric Artery - Branches off dorsal aorta
Renal arteries - Branch off dorsal aorta, lead to kidneys
Ovarian/testicular arteries - lead to the gonads
Iliolumbar arteries - Carry blood to the dorsal body wall
Inferior mesenteric artery - Branches off dorsal aorta, carries blood to the colon and rectum
Left and right common arteries - Branch off the dorsal aorta and branch out, supplying blood to the reproductive organs and hind limbs

Question 24

Name and describe the visceral veins of a rat

Answer 24

Left and right common iliac veins - Flow into the inferior vena cava
Inferior vena cava - Enters the liver where the hepatic vein enters it, then continues into the right atrium
Renal veins - Flow into the kidneys
Ovarian and testicular veins - Flow into the gonads
Iliolumbar veins - Paired veins below ovarian/testicular veins

Question 25

Describe the difference between invaginated and evaginated respiratory organs

Answer 25

Invaginated respiratory organs are in-folded (the folds are internal), an example of this is the lungs.
Evaginated respiratory organs are out-folded (the folds are external), an example of this is gills